Fire extinguishing method and apparatus



Oct. 30, 1945. H. v. WILLIAMSON 2,337,963

4 FIRE EXTINGUISHING METHOD AND APPARATUS Filed Dec. 15, 1943 3Sheets-Sheet l FIRE EXTINGUISHING METHOD AND APPARATUS g xy;

Patented Oct. 30, 1945 FIRE EXTINGUISHING METHOD AND APPARATUS HildingV. Williamson, Chicago, IlL, assignor, by mesne assignments, toReconstruction Finance Corporation, Chicago, 111., a corporation of theUnited States.

Application December 15, 1943, Serial No. 514,417

21 Claims.

This invention relates to new and useful improvements in methods andapparatus for extinguishing fires by means of a fire extinguishingmedium formed of carbon dioxide and water 08. and constitutesimprovements over the method and apparatus disclosed and claimed in theapplication to'Leonard D. Myers, Serial No. 492,458, filed June 26,1943.

Water fog that is now commercially used by itself as a fireextinguishing medium and that is used in combination with carbon dioxidein accordance with the teachings of the aforesaid application isgenerated in an atomosphere of air. That is to say, the atomization orbreaking up or the solid streams of water into fine, individual waterdroplets or particles to form the fog takes place in a zone that issurrounded by 'air. Consequently, the generated water fog is dischargedfrom this zone with air filling the voids or spaces between theindividual droplets or particles throughout the angle or projection ofthe fog discharge. This void or space filling air is carried to the zonof application of the water fog on the fire and provides the fire withcombustion supporting oxygen.

It is one of the primary objects of this invention to generate in acarbon dioxide atmosphere water fog that is to beused in theextinguishment of fires.

A still further important object of the invention is the provision of amethod of and apparatus for producing an improved fire extinguishingmedium composed of pre-formed water g combined with carbon dioxide snowand vapor and in which the water fog is generated in an atmosphere ofcarbon dioxide so as to exclude air from the voids or spaces between thefine water droplets of the fog that is delivered to the carbon dioxide.

In my application Serial No. 425,568, filed January 3, 1942, I havedisclosed and broadly claimed carbon dioxide discharge apparatus for usein extinguishing fires. By means of this apparatus liquid carbon dioxideis suddenly reduced in pressure to effect its conversion to a mixture ofsnow and vapor. Between the zone of pressure reduction and the zone ofdischarge to the atmosphere the snow or vapor mixture is manipulated soas to effect separation of the snow and vapor components. The finaldischarge stream is produced with the carbon dioxide snow forming itscore and the carbon dioxid vapor forming a protective envelope aroundthe snow. This discharge apparatus is of such construction that thecarbon dioxide vapor is released to the atmosphere at a plurality ofpoints or zones that are spaced circumferentially around the peripheryof the dense snow core. Although these separate discharges of vapor flowor blend together by the time they have traveled a very short distancefrom the face of the discharge apparatus, and beyond their points ofblending a solid or continuous envelope is provided, the fact remainsthat the periphery of the dense snow core is exposed to the surroundingair through the spaces formed between the separated discharges of thevapor, This permits the snow to entrain air through these spaces andthis entrained air, naturally, is carried to the fire and results insupplying combustion supporting oxygen.

It is another primary object of this invention to effect the deflectionor some of the carbon dioxide vapor from the several separate dischargesinto the spaces between such discharges so that these spaces will besealed or filled up against the admission of air to the dense snow core.

Still another important object of the invention is the provision of amethod of and apparatus for producing a fire extinguishing mediumdischarge that is composed of a dense core of carbon dioxide snow, fromwhich the surrounding air is completely excluded, and a snow coreenclosing envelope which is formed of carbon dioxide vapor and waterfog, with the water fog being generated in an atmosphere that is formedby the carbon dioxide vapor.

Other objects and advantages of the invention will be apparent duringthe course of the following description.

In the accompanying drawings forming a part of this specification and inwhich like numerals are employed to designate like parts throughout thesame,

Figure 1 is a front elevational view of one form of fire extinguishingdischarge apparatus embodying this invention,

Figure 2 is a transverse sectional view taken on line 2--2 of Fig. 1,

Figure 3 is a perspective view of a water fog generating and carbondioxide vapor deflecting head which is illustrated in Figs. 1 and 2 asbeing employed in suitable numbers as a part of v the dischargeapparatus,

Figure 4 is a transverse sectional view of the head shown in detail inFig. 3,

Figure 5 is a front elevational view of .a modified form of fireextinguishing discharge appara-- tus embodying this invention, and

Figure 6 is a transverse sectional view taken on line liof Fig. 5.

In the drawings, wherein for the purpose of illustration is shown thepreferred embodiment of this invention, and first particularly referringto Figs. 1 to 4 inclusive, the reference character ll designates a pipeline that supplies liquid carbon dioxide to the illustrated dischargeapparatus. It should be considered that this supply pipe [I isrepresentative of either a play-pipe" which is attached to the outer endof a fire hose, or of a branch supply pipe that forms a part of a "fixedsystem." .The pipe II is threaded at its end |2 for connection to theshank or stem l3 of the discharge apparatus. This shank or stem isprovided with a bore I4 through which liquid carbon dioxide is deliveredto the interior of the body of the discharge apparatus. The forward endI5 01 this bore communicates with the interior of a deflector elementand cooperates with this element to form a flow path for the liquidcarbon dioxide. Formed on the outer end of the shank or stem I3 is aradially extending flange l6 that is formed with a circular series oforifices I! through which the liquid carbon dioxide is released topermit it to suddenly expand so that its pressure will drop below 75pounds per square inch, absolute, which will cause all or a majorportion of the liquid to flash and form a mixture of snow and vapor. Acircular series of threaded openings 3, also, is formed in the flange l6for a purpose to be explained at a later point. The exterior of theshank or stem I3 is provided with a rearwardly curved or flared surfaceI9 that terminates in a rearwardly facing shoulder 20.

The above referred to deflector element is identified by the referencecharacter 2| in Figs. 1 and 2. The annular flange I6 of the shank orstem I3 is employed for mounting this deflector element and the seriesof screws 22, threaded into the holes l8 of the flange attaches thedeflector element to the shank or stem. By inspecting Fig. 2, it will benoted that the deflector element 2| is partially hollowed out so as tocontrol the direction of flow of the liquid carbon dioxide from theshank bore M to the discharge orifices IT. The interior of the deflectorelement 2| is provided with a conicaliy shaped projection 23 for thispurpose and this projection is axially aligned with the bore l4 of theshank or stem. Radially outwardly of the projection 23 the interior ofthe deflector element 2| is provided with the curved surface 24 that isutilized to change the direction of flow of the liquid carbon dioxide sothat it will be directed rearwardly through the discharge orifices H.The rear portion of the deflector element 2| is belled or curvedoutwardly at 25 to form an internal, curved surface 26 that liesopposite to and cooperates with the exteriorly curved surface IQ of theshank or stem I3. It is clearly shown by Fig. 2 that these twocooperating, curved surfaces i9 and 26 diverge with respect to eachother in any radial section to form an annular passageway that graduallyincreases in thickness or depth to permit further expansion of thereleased carbon dioxide so that the pressure of the same will be certainto drop below the aforesaid 75 pound pressure value to provide forcomplete flashing of all of the liquid carbon dioxide to a mixture ofsnow and vapor.

The front portion of the deflector element 2| is illustrated in Figs. 1and 2 as being formed with radially extending ribs 21 to formtherebetween the valleys 28. These valleys are provided with curvedinner surfaces 29 that function to deflect forwardly or axially of thedischarge apparatus any of the medium which comes in contact with thesame.

Fig. 2 clearly shows that the deflector element 2| and the cooperatingportionof the shank or stem III are enclosed within a chambered body orcasing which is formed by the inner portion 30 and the outer portion 3|.The inner body or casing portion 30 is dish shaped and is centrally cutaway at 32 to permit the inner portion of the shank or stem l3 to passthrough the same for engaging the shoulder 20 with the part of the saidportion 30 which surrounds the Opening 32. This shoulder 20, therefore,acts as a seat or an abutment for mounting the inner portion 30 of thebody or easing. Any suitable means may be provided for securing thecasing or body portion 30 to the shoulder portion 20 of the shank orstem, such as by welding or the use of suitable screws. The outerportion 3| of the body or casing is of cylindrical shape and has itsinner edge portion telescopically associated with the outer marginaledge portion of the inner body part 30 to provide a suitable joint 33that may be rendered permanent by welding. It is clearly shown in Figs.1 and 2 that the body or casing of the discharge apparatus cooperateswith the shank or stem I3 to provide a closed rear wall while leavingthe front or face of the apparatus entirely open. An annular chamber isformed by the cooperation of the body or casing with the stem or shankl3 and the deflector 2| and this chamber receives the circular series offlow controlling and directing units 34.

These units 34 extend radially of the shank or stem 3 and the deflectorelement 2| and are equally spaced therearound. Each one of these unitsincludes a semi-circular cr semi-cylindrical band 35 which is flanged atboth of its longitudinal edges 36, as best illustrated in Fig. 2. Theinner transverse edge 31 of each one of these bands 35 is suitablyanchored either in close proximity to or in contact withthe periphery ofthe flared portion or surface IQ of the stem or shank 3. Each one ofthese bands 35 has its outer edge 38 terminating in the plane of theouter face of the body or casing portion 3| and the outer edges of theribs 21 that form a part of the deflector element 2|.

Each one of the flow controlling anddirectin units 34 has its oppositesides formed by wall members 39 which lie inside the edge flanges 36 ofthe bands 35 and are suitably secured thereto. Figs. 1 and 2 of thedrawings clearly show that the opposite side walls of each adjacent pairof units 34 are formed by a single piece of sheet material with thecenter or intermediate portion of each one of these pieces beingdesignated by the reference character 40. These portions 40 function tobridge the gaps or spaces that would otherwise be formed between theinner edges or sides of adjacent units 34.

These side wall members 39 of the several units 34 are clearly shown inFig. 2 as having apertures 4| formed therein. This figure also clearlyshows that these apertures are formed in the forward halves of the sidewall members 39, or relatively close to the outer edges 38 of the bands35. Mounted within each one of the flow controlling and deflecting units34 is a plow-shaped deflecting and separating element 42 which is wedgeshape in section and is provided with the securing flanges 43 at itssides by means of which the elements 42 may be welded, or otherwisesecured in place within their respective units 34. These deflecting andseparating elements 43 are shown in Fig. 2 as being arranged withrespect to the through the cooperating side wall openings orapertures4|. Fig. 2 shows these elements 42 as being arranged so that their outertransverse edges 45 are spaced from the inner surfaces of the outer endportions of their associated bands 35. A space or gap is thus leftbetween the inner surface of the band 35 of each unit 34 and the outeredge 45 of its associated element 43 through which extinguishingmaterial may flow to the outer edge 38 of the band 35.

The carbon dioxide discharge apparatus thus far described operates inthe following manner. Liquid carbon dioxide, at any desired temperature,and its corresponding vapor pressure, will be delivered by the pipe lineH to the bore l4 of the shank or stem l3 and will flow as a liquid tothe discharge orifices I1. In leaving these orifices, the liquid carbondioxide expands suddenly and drops in pressure to such an extent that itflashes and vapcrizes. The carbon dioxide that enters the space formedbetween the outwardly flared surfaces [3 and 25, therefore, takes theform of a mixture of snow and vapor. A certain percentage of the liquidcarbon dioxide passing through the oriflces II will flash into snow as aresult of the self-cooling action that is produced. The percentage ofsnow yield will depend upon the temperature of the liquid carbon dioxidethat is provided to the discharge apparatus. In other words, a mixtureof snow and vapor will be discharged from the peripheral mouth that isformed by the outer edges of the curved surfaces l9 and 26.

As it leaves this peripheral mouth, the snow and vapor mixture will beflowing in a truly radial direction and certain portions of the mixturewill pass directly into the various flow controlling and directing units34. The remainder of the mixture will be split and deflected laterallyin opposite directions by the axially extending portions 40 of thesidewall forming pieces 39. These deflected portions of the mixture,therefore, will be directed into the several units 34. The flowcontrolling and directing units 34, through the medium of their curvedouter bands 35, will deflect the flowing snow and vapor mixture from itsstraight line, radial path and will convert this radial flow into acurvilinear flow or motion. As the carbon dioxide snow of the mixture ismany times more dense than the vapor, and as the velocity of both ofthese components is the same, the snow offers more resistance to thedeflecting forces exerted by the obstructing, curved bands 35 with theresult that the snow will be moved to the outer portion of each one ofthese curvilinear flow paths. The snow, in seeking this outer portion ofeach path, will crowd or force the vapor inwardly away from the innersurface of the curved band that forms the path. Therefore, thedifference in density between the snow and the vapor effects asegregation of these two components. The snow is segregated at or closeto the outer Surface of each one of the curvilinear paths and the vaporis segregated on the inner side of each path.

As the segregated snow and vapor reach the outer side of each one of theflow controlling and directing units 34, the snow passes through the gapor space left between the inner surface of its band 35 and the outeredge of its flow splitting and separating element 42. The inwardlydisplaced or segregated vapor strikes the sloping surfaces 44 of thevarious elements 42 and is directed laterally through the side wallapertures 4| into the portions of the body or casing which lie betweenadjacent units 34. The segregated and separated snow passes radiallyoutwardly beyond the edges 33 of the several bands 33 and is directedinto the valleys 23 of the deflector element 2|. The curved innersurfaces 23 of these valleys deflect the snow so that it will flow intothe atmosphere in an axial direction with respect to the entireapparatus. This. discharge of all of the separated snow from all of theunits 34 causes the same to be assembled into a compact, dense stream.The separated vapors will leave the spaces between the adjacent units 34and will flow in an axial direction relative to the discharge apparatus.The vapor is in this way discharged outwardly of the dense snow coreportion of the stream. Because the areas of discharge for the vapor arespaced distances equal to the width of the flow controlling anddirecting units 34, the vapor discharges will be separated from eachother immediately adjacent the front face of the apparatus. However, thevapor discharges will blend together a short distance in advance of theapparatus and will form a surrounding or enclosing vapor tube for thecompact, dense snow core of the composite discharge stream. Because ofthis spacing of the separate vapor discharges, it will be appreciatedthat the compact, dense snow core is exposed. to the air of thesurrounding atmosphere and unless some means are provided for preventingsuch an action, air can be sucked radially inwardly of the dischargeapparatus at the locations of the several flow controlling and directingunits 34 and this inwardly drawn air will be entrained by the dense snowcore.

From this description of the mode of operation of the dischargeapparatus for the liquid carbon dioxide, it will be appreciated thatthere is provided a discharge stream which is of substantiallycylindrical shape in transverse section. Fig. 2 of the drawings showsdotted lines A and B which are intended to represent the peripheralmargins of this stream on the section of this figure. The dotted lines Cand D are intended to illustrate the peripheral margins of the compact,dense snow core. It will be appreciated, therefore. that the margins ofthe vapor tube or envelope are represented by the dotted lines A-C andB-D.

The apparatus for generating and projecting the water fog that is to becombined with the carbon dioxide discharge now will be described. Ahollow water supplying manifold. or ring 46 surrounds the outer edgeportion of the body or casing part 3! and is suitably secured thereto bymeans of the several branch pipes 41 which are connected to the innerside of the ring 46 and pass through suitable openings formed in thebody or casing part 3|. A water feed pipe 48 is suitably connected tothe nipple 49 that is attached to the manifold or ring 43 at anysuitable point. This pipe 48 delivers water to the ring or manifold andthis water flows through the several branch lines 41 at a uniform rate.The water supply to the ring or manifold 46 may be under any suitablepressure head but it has been determined that the best water foggingaction is obtained when pressures ranging from pounds to 200 pounds persquare inch are employed.

By inspecting Fig. 1, it will be seen that the various branch lines 41extend into the carbon dioxide vapor discharge spaces that are locatedbetween adjacent pairs of flow controlling and directing units 34. Theinner end of each one of these branch lines 41 has suitably mountedthereon a head 50. One of these heads is shown in detail in Figs. 3 and4. Each head has a hollowed out box-like main body portion 5!, theinterior of which communicates with the bore of a branch line 41 so thatwater is delivered to the interior of each one of these box-like bodies.-The front face of each box-like body is formed by the two angularlyarranged wall portions 52 and 53. These wall portions are provided witha suitable number of discharge apertures 54 and 55 respectively. Due tothe angular arrangement of the wall portions 52 and 53, and the opposedpositions of the apertures 56 and 55, the water streams dischargedthrough opposed apertures will impinge with the result that the Waterwill be thoroughly atomized to produce the desired Water fog. Byinspecting Fig. 1, it will be seen that the fog generated by each head55 will be protected or shielded from the surrounding atmosphere by thecarbon dioxide vapor that is discharged at the locations identified bythe reference character a. The generated water fog, also, will beshielded from the dense snow core by the carbon dioxide vapor that isdischarged through the areas identified by the reference character 1).

Figs. 1, 3 and 4 disclose laterally projecting wings 56 as being formedon the opposite sides of the box-like body portions 5i of the severalheads 50. The inner sides of these wings 56 are of wedge shape, asindicated by the reference character 51. It will be appreciated,therefore, that these laterally projecting wings 56 and their Wedgeshaped rear surfaces 51 will function to deflect or spreadcircumferentially of the entire discharge apparatus the carbon dioxidevapor which would normally flow axially through the spaces occupied bythese several heads 50. This circumferentially deflected vapor willfunction to close or seal ofi the spaces or areas lying in front of theflow controlling and directing units 34 with the result that thesespaces will no longer be open for the passage of air from thesurrounding atmosphere into the compact, dense snow core. Thecircumferentially deflected carbon dioxide vapor that leaves the outeredges of the wings 56 will additionally seal off or close the remainingtwo sides of the zones in which the water fog is generated by the everalheads. It will be appreciated, therefore, that the water fog isgenerated by each head 50 in a carbon dioxide vapor atmosphere.Consequently, carbon dioxide vapor will fill the voids left between theindividual water droplets or particles of the fog. It further will benoted that the generated fog will be projected in the carbon dioxidevapor portion of the composite discharge; i. e., the annular areadefined by the dotted lines A and 3-D of Fig. 2.

Figs. and 6 disclose a modified form of carbon dioxide and water fogdischarging apparatus. The carbon dioxide discharging portion of thismodification is identical with the carbon dioxide discharging apparatusof Figs. 1 and 2 and for that reason the same reference characters willbe applied to identical elements and a second detail description ofthese elements will not be presented.

The water fog generating mechanism of the embodiment shown in Figs. 5and 6 is some what different than the fogging mechanism previouslydescribed. In this second embodiment,

the water supplying manifold or ring 58 is located at the rear of or inback of the carbon dioxidedischarge apparatus. This manifold or ringreceives its supply of water under pressure from the pipe line 59 thatis connectedto the ring by the nipple 50.

A suitable number of branch lines ii are connected to the water supplymanifold or ring 58 and extend axially of the carbon dioxide dischargeapparatus at the inner sides of the several spaces through which thecarbon dioxide vapor flows to the discharge face of the apparatus. Thatis to say, these branch lines 6i lie parallel to and just outside of theconnecting portions 40 of the side wall forming pieces 39.

To the front end of each one of these branch lines 6| there is connecteda-hollow water fogging head 62. Each one of these heads has its frontface formed by the two angularly arranged wall portions 63 and 6t.Discharge apertures 65 and 66 are formed in these wall portions 65 and64 respectively. The'apertures 65 and 66 of each discharge head arearranged in radial alignment with respect to the entire dischargeapparatus and, due to the angular relation of the wall portions 63 andEd in which the apertures are formed, the streams of water dischargedthrough each pair of apertures will impinge to eifect fog generation.

. It will be obvious from an inspection of the two figures, andparticularly Fig. 5, that the water fo generated by the various heads 62will be projected into both the vapor and the snow portions of thecarbon dioxide discharge stream.

Also, the water fog generated by all of the heads 52 will have the voidsbetween the individual water droplets filled with carbon dioxide insteadof air.

This discharge apparatus of Figs. 5 and 6 clearly is not as efllcient oreffective as the discharge apparatus of Figs. 1 to 4 inclusive. Thedeflciencies of this modification result from the failure to deflect orspread some of the dischargin vapor circumferentially to fill in or sealthe spaces or gaps that are produced by the flow controlling anddeflecting units 34. Additionally, it has been determined that a moreefficient, effective composite discharge is produced when the water fogis mixed with the carbon dioxide por only.

It is to be understood that the forms of this invention herewith shownand described are to be taken as preferred examples of the same and thatvarious changes in practicing the hereindescribed method, and in theshape, size, and arrangement of parts of the apparatus shown as beingcapable of carrying out the method, may be resorted to without departingfrom the spirit of the invention or the scope of the subjoined claims.

Having thus described the invention, I claim:

1. A method of dischargin a fire extinguishing medium, comprisingconducting liquid carbon dioxide to a region of release, permittingsudden expansion of the liquid to produce snow and vapor, projecting thesnow and vapor into the atmosphere in the form of a stream, generatingwater fog entirely independently of any force exerted by the projectedsnow and vapor and at a location that is completely surrounded by thecarbon dioxide stream so that the voids between the droplets of the fogwill be fllled with carbon dioxide, and so projecting the water fog thatit will be carried to the point of application by the carbon dioxidestream.

2. A method of discharging a fire extinguishing medium, comprisingconducting liquid carbon dioxide to a region of release, permittingsudden expansion of the liquid to produce snow and vapor, projecting thesnow and vapor into the atmosphere in the form of a stream, separatelygenerating water fog by the impingement of streams of water within theconfines of the carbon dioxide stream so that the voids between thedroplets of the fo will be filled with carbon dioxide, and so projectingthe water log that it will be carried to the point of application by thecarbon dioxide stream.

3. A method of discharging afire extinguishing medium, comprisingconducting liquid carbon dioxide to a region of release, permittingsudden expansion of the liquid to produce snow and vapor, projecting thesnow and vapor into the atmosphere in the form of a stream, separatelygenerating water fog at a plurality of points distributed over the crosssection of the carbon dioxide stream so that the voids between thedroplets of the fo will be filled with carbon dioxide, and s projectingthe water fog that it will be carried to the point of application by thecarbon dioxide stream. I

4. A method of discharging a fire extinguishin medium, comprisingconducting liquid carbon dioxide to a region of release, permittingsudden expansion of the liquid to produce snow and vapor, projecting thesnow and vapor into the atmosphere in the form of a stream, separatelygeneratin water fog at a plurality of points distributed over the crosssection of the carbon d1? oxide stream by the impingement of two streamsof water at each point so that the voids between the droplets of the fogwill be filled with carbon dioxide, and so projecting the water fog thatit will be carried to the point of application by the carbon dioxidestream.

5. A method of discharging a. fire extinguishing medium, comprisingefiecting sudden release of liquid carbon dioxide to lower its pressuresufficiently to form a mixture of snow and vapor, effecting separationof the snow and vapor from each other, formin the separated snow andvapor into a composite discharge stream, separately generating water fogwithin the confines of the carbon dioxide stream so that the voidsbetween the droplets of the fog will be filled with carbon dioxide, andso projecting the water fo that it will be carried to the point ofapplication by the carbon dioxide stream.

6. A method of discharging a fire extinguishing medium, comprisingeffecting sudden release of liquid carbon dioxide to lower its pressuresufficiently to form a mixture of snow and vapor, effecting separationof the snow and vapor from each other, forming the separated snow andvapor into a composite discharge stream, separately generating water fogwithin the confines oi the carbon dioxide vapor portion of the stream sothat the voids between the droplets of the fog will be filled withcarbon dioxide vapor, and so projecting the water fog that it will becarried to the point of application by the carbon dioxide vapor portionof the stream.

7. A method of discharging a fire extinguish ing medium, comprisingefiecting sudden-'release of liquid carbon dioxide to lower its pressuresufficiently to form a mixture or snow and vapor, efiecting separationof the snow and vapor from each other, formin the separated snow andvapor components into a composite discharge stream with the vaporshielding the snow from the surrounding atmosphere, separatelygenerating water fog within the confines of the carbon dioxide vaporportion of the stream so that the voids between the droplets of the fogwill be filled with carbon dioxide vapor, and so projecting the waterfog that it will be carried to the point of application by the carbondioxide vapor portion of the stream.

8. A method of discharging a fire extinguishing medium, comprisingefiecting sudden release of liquid carbon dioxide to lower its pressuresufficiently to form a mixture of snow and vapor, effecting separationof the snow and vapor from each other, forming the separated snow andvapor component into a composite discharge stream, separately.generating water fog at a plurality of points distributed over the crosssection of the carbon dioxide vapor portion of the stream so that thevoids between the droplets of the fog will be filled with carbon dioxidevapor, and .so projecting the water iog that it will be carried to thepoint of application by" the carbon dioxide vapor portion of the stream.

9. A method of discharging a fire extinguishing medium, comprisingeffecting sudden release of liquid carbon dioxide to lower its pressuresufficiently to form a mixture of snow and vapor. effecting separationof the snow and vapor from each other, forming the separated snow andvapor into a composite discharge stream with the vapor shielding thesnow from the surrounding atmosphere, separately generating water fo ata plurality of points distributed over the cross section of the carbondioxide vapor portion of the stream so that the voids between thedroplets of I the fog will be filled with carbon dioxide vapor, and soprojecting the water fog that it will be carried to the point ofapplication by the carbon dioxide vapor portion of the stream.

10. A method of discharging a fire extinguishing medium, comprisingdischarging carbon dioxide snow and vapor to the atmosphere in the formof a stream in which .the snow :and vapor occupy different portions ofthe stream cross section, generatin water fog within the confines of thecarbon dioxide discharge so that the voids between the droplets of thefog will be filled with carbon dioxide, and forming the carbon dioxideand the water fog into a composite discharge stream.

11. A method of discharging a fire extinguishing medium, comprisingdischarging carbon dioxide snow and vapor to the atmosphere in the formof a stream in which the snow and vapor occupy different portions of thestream cross section, generatin water fog in the confines of the carbondioxide vapor portion of the stream so that the voids between thedroplets of the fog will be filled with the vapor, and forming thecarbon dioxide and the water fog into a comosite discharge stream.

12. A method of discharging a fire extinguishing medium, comprisingconducting liquid carbon dioxide to a region of release, permittingsudden expansion of' the liquid to produce snow and vapor, efiectingseparation of the snow and vapor from each other, discharging the carbondioxide to the atmosphere with the separated snow forming a single densestream and with the separated vapor forming several streams spacedcircumferentially around the snow stream, and deflecting some of thevapor circumferentially to fill in the spaces between the several vaporstreams to prevent the snow stream from entraining air through saidspaces.

13. A method of discharging a fire extinguishing medium, comprisingconducting liquid carbon dioxide to a region of release; permittingsudden expansion of the liquid to produce snow and vapor, eiTectingseparation of the snow and vapor from each other, discharging the carbondioxide to the atmosphere with the separated snow forming a single densestream and with the separated vapor forming several streams spacedcircumferentially around the snow stream, generating water fog in thepath of each one of the vapor streams so that the voids between thedroplets of the fog will be filled with the vapor,

' and so projecting the water fog that it will be carried to the pointof application by the carbon dioxide.

14. A method of discharging a fire extinguishing medium, comprisingconducting liquid carbon dioxide to a region of release, permittingsudden expansion of the liquid to produce snow and vapor, effectingseparation of the snow and vapor from each other, discharging the carbondioxide to the atmosphere with the separated snow forming a single densestream and with the separated vapor forming several streams spacedcircumferentially around We snow stream, deflecting some of the vaporcircumferentially to fill in the spaces between the several streams toprevent the snow stream from entrainin air through said spaces,generating water fog axially outwardly of each point of deflection ofthe vapor so that the z e of generation will be enclosed in the vaporand the voids between the droplets of the fog will be filled with thevapor, and so projecting the water fog that it will be carried to thepoint of application by the carbon dioxide.

15. Fire extinguishing apparatus, comprising a hollow body, means forreleasing carbon dioxide into said body to permit it to suddenly expandto form carbon dioxide snow and vapor, means in the hollow body toeffect discharge of the snow and vapor to the atmosphere as a stream,-and means for generating water fog entirely independently of any forceexerted by the projected snow and vapor and at a location that iscompletely surrounded by the snow and vapor of the carbon dioxide streamso that the voids betweenthe water droplets of the fog will be filledwith carbon dioxide and for projecting the generated water fog 50 thatit will be carried to the point of application by the carbon dioxidestream.

16. Fire extinguishing apparatus, comprising a hollow body through whicha mixture of carbon dioxide snow and vapor passes, means within the bodyfor separating snow and vapor from each other while passing therethroughand for discharging the same to the atmosphere with the vapor shieldingthe snow from the surrounding atmosphere, and means for generating waterfog within the vapor portion of the carbon dioxide discharge so that thevoids between the droplets of the fog will be filled with carbon dioxidevapor and for projecting the generated water fog into the flow path ofthe carbon dioxide stream for entrainment thereby.

17. Fire extinguishing apparatus, com-prising a hollow body, means forreleasing liquid carbon dioxide into said body to permit it to suddenlyexpand to form snow and vapor, means in the hollow body to effectdischarge of the snow and vapor to the atmosphere as a stream, and meansfor generating water fog at a plurality of points distributed over thecross section of the carbon dioxide stream so that the voids betweenthe. droplets of the fog will be filled with carbon dioxide.

18. Fire extinguishing apparatus, comprising a hollow body through whicha mixture of carbon dioxide snow and vapor passes, means within the.

body for separating the snow and the vapor from each other while passingtherethrough and for discharging the same to the atmosphere with thevapor shielding the snow from the surrounding air, and means forgenerating water fog at aplurality of points distributed over the pathof the vapor discharge so that the voids between the droplets of the fogwill be filled with carbon dioxide vapor.

19. Fire extinguishing apparatus, comprising a hollow body through whicha mixture of carbon dioxide snow and vapor passes, means witl 'n thebody for separating the snow and the vapor from each other while passingtherethrough and for discharging the snow as a single dense stream andthe vapor as several streams spaced circumferentially around the snowstream, and means located in the path of each vapor stream fordeflecting some of the vapor circumferentially to fill in the spacesbetween the several vapor streams to prevent the snow stream fromentraining air through said spaces.

20. Fire extinguishing apparatus, comprising means for dischargingcarbon dioxide to the atmosphere, and means for generating water fogentirely independently of any force exerted by and at a location that iscompletely surrounded by the carbon dioxide discharge so that the voidsbetween the droplets of the fog will be filled with carbon dioxide.

21. Fire extinguishing apparatus, comprising means for dischargingcarbon dioxide snow to the atmosphere as a dense stream, means fordischarging carbon dioxide vapor to the atmosphere as several streamsspaced circumferentially around the snow stream, and means operativelyassociated with the carbon dioxide vapor streams for deflecting some ofthe vapor circumferentially I of the snow stream to fill in the spacesbetween the vapor streams to prevent the snow from entraining airthrough said spaces.

HILDING V. WILLIAMSON.

